The present invention relates to container packaging and more particularly to sheet material for secondary container packaging.
The term "secondary container packaging" as generally understood in the industry and as used herein refers to packaging used in conjunction with primary containers, such as cans or bottles, which contain the ultimate product, such as beer or other beverages. Secondary container packaging includes container wraps which surround and support the containers, basket bottle carriers having bottom and side supports for the containers and an upwardly extending handle, 12-pack rectangular carriers completely enclosing the containers, and labels for application to the containers. Most secondary container packaging is made of paper, or paperboard, typically so-called carton or carrier board. Carrier board is specifically manufactured to be used for secondary container packaging. High strength is desired, so the board is usually produced from virgin, strong fiber and contains chemical additives to resist moisture. A smooth white surface is then coated on the carrier board with a white clay-titanium dioxide-latex mixture. The white surface is added to permit decoration of the naturally brown, rough surface of the carrier board. In some cases, as in the secondary container package described in U.S. Pat. No. 3,603,501, a white outer surface is provided through the lamination of an outer thin layer of high-quality label paper to a thicker backing material. Plastic is also used in some secondary container applications, such as in a bottle carrier formed from plastic sheet described in U.S. Pat. No. 3,815,947, and in webs of plastic rings fitted around the necks of beverage cans as described, for example, in U.S. Pat. No. 3,086,651.
The main objectives of secondary container packaging are shipping and handling strength and attractive consumer appearance. The two key aspects of packaging strength are tensile load strength, relating to the resistance of the material to diametrically opposed forces and tear strength, relating to the internal resistance of the material to tearing. Since the consumer purchases the packaging only incidentally to the container contents, these objectives must be met within the overriding criterion of cost.